Field of the Invention
The present invention concerns a method for generating a three-dimensional multi-slice data set of a heart, and a tomography apparatus for generating a three-dimensional multi-slice data set of a heart.
Description of the Prior Art
Two methods of acquiring moving images of a heart and calculating a heart function therefrom currently exist in cardiac magnetic resonance tomography (MRI—Magnetic Resonance Imaging). With retrospective gating, the heartbeat frequency of the patient barely changes during the measurement time, so that a reconstruction of an average heartbeat cycle is enabled. This average heartbeat cycle effectively reproduces the typical heartbeat of the patient. The other basic method is prospective gating, which is used for patients whose heartbeat frequency changes during the acquisition duration, since the changes in the interval duration can generate artifacts during retrospective gating. Although prospective gating is the sole solution for patients with arrhythmic heartbeats, this method is infrequently used because of its lower resolution compared with retrospective gating.
New acquisition methods, such as for instance iterative reconstruction, allow a comparable acquisition resolution to that which is currently possible with retrospective gating. A further factor with prospective gating is, however, that the heart function cannot be reliably calculated with the acquisition of a single heartbeat, since the heartbeat has a different duration for each recorded individual slice of the heartbeat, which results in different function results. In these cases, the examination results depend to a high degree on the experience and subjective estimation of the radiologist or cardiologist.
U.S. Pat. No. 4,903,704 disclosed a method in which the acquisition of data is stopped upon the occurrence of irregularities in the heartbeat. After a waiting time of several heartbeats, the acquisition of data is resumed.